Re: Re: [xine-devel] Interlaced video

[Arpi <ar...@th...>]

Hi,

> On Thu, 2002-04-04 at 09:27, KAY Robin wrote:
> > Switching the video out plugin between interlaced and non interlaced
> > currently requires manual intervention. Do any of the video formats
> > supported by xine contain information about whether the video is
> > interlaced or not, and if so could this information be passed on to the
> > video output plugin. I am thinking of primarily of DVDs where the video
> > is interlaced but still frames are not (and they look better without
> > being passed through the deinterlacer).
> 
> I remember reading somewhere that interlacing information (if it's
> progressive or not) from mpeg2 is not actually used by dvd producers. So
> i guess reporting this flag to video drivers will be quite useless...

the mpeg decoder actually knows if the frame is interlaced or not.
there are 2 different form of interlacing:
- real interlaced video - the decoder will see 2 fields instead of 1 frame
  with libmpeg2, check for picture->picture_structure!=FRAME_PICTURE
- interlaced video source encoded as frames
  it's either unwatchable ugly _or_ uses interlaced DCT.
  in later case, the decoder will know about it...
  also note, that these streams usually are progressive, so the progressive
  and repeat_first_field flags are set in extension headers.

for mjpeg, the jpg header contains flag telling you if it's frame or fields.
but the field order is a problem, .mov files has stsd extension 'fiel' for this,
for avi i have no idea, maybe bitmapinfoheader user data has such info


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu